Idaho, constituent state of the United States of America. Its area is twice that of the six New England states combined. Its boundaries—with the Canadian province of British Columbia to the north and the U.S. states of Montana and Wyoming to the east, Utah and Nevada to the south, and Oregon and Washington to the west—are both historical and geographic in derivation. The boundary with British Columbia follows the 49th parallel of north latitude, while the border with Utah and Nevada follows the 42nd parallel; both lines were established by treaty—the northern between the United States and Britain in 1846 ... (100 of 5,035 words)